Breech block for a gun



July 30, 1957 K. B. BRA'THE BREECH BLOCK FOR A GUN juil 30, i957 K. B. BRATHE 00,37

BREECH BLOCK FOR A GUN Filed on. 21, 1952 s shams-sheet 2 Lv v50/vra@ @RL Bizar/1. Bk/9 THE K. B. BRATHE BREECH BLOCK FOR A GUN my 30e, w57

3 Sheets-Sheet 3 Filed oct. A 21, 1952 I/wA/ro/Q Imm. EfRr/A @Hf/f5 m uw w R o r T H `BREECH BLOCK FOR A GUN Karl Bertil Brthe, Karlskoga, Sweden, assignor to Aktiegolaget Bofoxs, Bofors, Sweden, a corporation of weden The present invention relates to a breech-loading gun and, more especially, to improvements in the breech block mechanism therefor.

In modern guns of the breech-loading type, and particularly in large-caliber guns and cannon, a breech block is employed for opening and closing the barrel chamber in order to permit insertion of a projectile into the barrel chamberand subsequentfring of the gun. Accordingly, the breech block is arranged in such a manner within the breech ring of the gun as to be readily moved so as alternately to open and close the gun chamber. Furthermore, the development of modern,`high-power, rapid-tire guns has rendered obsolete thev relatively slow hand operation of theY breech block unless a slow rate of fire is suicient and has made necessary the extremely rapid mechanical actuation thereof.

In mechanically actuating the breech block, spring devices have commonly been employed, which devices are tensioned when the breech block is moved into open position permitting the insertion of a projectile into the barrel chamber. When the breech block is released subsequent to the loading operation, the spring tension operates to movethe breech block into its position closing the barrel chamber, this movement of the breech block being arrested by a pair of stop members disposed in the breech ring adjacent the respective end of the breech opening. In large-caliber, rapid-tire guns, the breech block will, of necessity, have considerable Weight and, furthermore, since positive closing of the barrel chamber prior to tiring is essential, the tension of the spring device actuating the `breech block must be very high. Thus, the combined effect of the weight of the breech block and of the required high spring tension imposes very great stresses on the aforementioned stop members, thereby necessitating solid and massive construction of said stop members.

Since massiveness of the stop members disposed within the breech ring is undesirable, numerous attempts have been made to decrease the stresses imposed upon the stop members. It has been attempted, for example, to mount the stop members resiliently. This has not proven satisfactory for the reason that when the breech block engages the resilient stop members it will rebound and oscillate. Obviously, positive closing of the barrel chamber and accurate firing of the gun cannot take place while and when the breech block is oscillating and the indicated arrangement has the considerable disadvantage that the ring of the gun must be delayed until the oscillating movement of the breech block has ceased.

- Accordingly, it is a primary object of the present invention to provide a breech block mechanism which obviates the diiculties and disadvantages of conventional construction and which is designed and arranged in such a manner as positively to decrease the speed of the movement of the breech block prior to the actual contact with the' stop members so that the stresses imposed onthe stop members will be reduced to a minimum.

Another object of the invention is to provide a breech block mechanism of the character indicated having im- 2,800,837 Patented July 30,' 1957 2 pact-absorbing members disposed in the breech ring of said mechanism for recprocation in the same direction as the breech block and arranged to withstand the major portion of the thrustof the breech block prior to its movement into a completely closed position.

A further object of the invention is to provide a breech block mechanism having impact-absorbing members of the character indicated and wherein the impact-absorbing members are operatively connected with a closed hydraulic system for damping the movement of the breech block during the latter part of its movement into the closed position.

The foregoing objects as well as additional objects and advantages of the inventionV will be readily apparent in the course of the following detailed description taken in connection with the yaccompanying drawing which illustrates a preferred embodiment of the invention, and wherein:

Fig. 1 is a fragmentary perspective view of a portion of a gun barrel adjacent to the breech ring thereof, the breech block mechanism incorporating the features of the invention andthe breechblock being shown in elevated position so that the barrel chamber is open.

Fig. 2 is a similar view but with the breech block in lowered position closing the barrel chamber.

Fig. 3 is similar to Fig. 2 but showing the barrel returning after recoil, and

Fig. 4 is an enlarged perspective view, partly in section, of one of the piston cylinders forming a part of the invention.

.Referring now to the figures in greater detail, reference numeral 1 designates a gun barrel provided at its rearward end with a breech ring 2. Within breech ring 2 there is deineda vertically extending breechopening 3, at the lower end of which is disposed a pair of opposed stop members 4 and S. projecting a short distance within said breech opening. A breechblock 6 is reciprocable Within breech opening 3 and is limited in its downward movement by the stop members 4 and 5. The cross-sections of breech opening 3 and breech block 6 are preferably complementary, as shown, so that said breech block is reciprocating slidable vwithin said breech opening between the elevated openpposition of Fig. 1 and the lowered closed position of Figs. 2 and 3. Breechblock 6 is provided on its front face with aV recess 7 for the reception of a tiring pin (not shown).

An actuating lever 8 controls the movement of breech block 6. One end of lever 8 is pivoted to said breech block and the other end of said lever is connected to a shaft 9 which is rotatably mounted in breech ring 2. Shaft 9 extends within a cylindrical casing 10 and is provided with'splines 11.' The means for actuating shaft 9 to control the motion of breech block 6 does not form a part of the present invention and, accordingly, is not illustrated. Casing 10 may be provided with a coil spring (not shown) which may be fastened at one end of the inner wall of the casing and the other end of which may be secured to shaft 9. Furthermore, shaft 9 is provided with a stop device (not shown) for locking breech block 6 in the elevated open position as illustrated in Fig. l.

An important feature of the invention resides in the provision Within breech ring 2 of a pair of impact-absorbing members or plungers 16 and 17 arranged for movement in the same direction as breech block 6 in order to withstand and counteract the major portion of the downward thrust of said breech block prior to its actual contact against stop members 4 and 5. For this purpose each impact-absorbing member or plunger 16 or 17 is arranged for reciprocation within the vertical bore 13 of a mounting element 12 secured to the wall of breech opening 3 adjacent the lower end thereof. In order toV simplify the drawings and make clear the operation of the mechanism both the plungers 16 and 17 are shown but only one mounting element 12 is illustrated. Plungers 16 and 17 are normally spring urged upwardly to protrude from their respective mounting elements 12 by means of coil springs `14 and 15 respectively, Vas clearly shown in Fig. 1. The upper protruding ends of plungers 16 and 17 are engaged during the downward movement of breech block 6 to its closed position by abutment faces 16a and 17a, respectively, formed on said breech block. The lower ends of plungers 16 and 17 bear against and actuate a pair of levers 18 and 19, the inner ends of which are pivoted in the bottom of the barrel jacket 20 of the gun. Said barrel jacket which, of course, does not recoil with the barrel 1 and breech ring 2, is provided with a pair of longitudinal slots 20a (see Fig. 3) in order to permit a free pivotal movement of levers 18 and 19. The free outer ends of levers 18 and 19 rest against the upper ends of piston rods 21 and 22, respectively, carried by closed cylinders 23 and 24, respectively. Cylinders 23 and 24 are connected to an oil tank 30 by means of conduits 25, 26, 27, 28 and 29 and couplings 31, 32 and 33.

Cylinders 23 and 24 are tixedly secured in any suitable manner to barrel jacket 20.

The construction and operation of the identical cylinders 23 and 24 will now be described with reference to Fig. 4. The upper end of each cylinder 24 is closed off by means of a screw plug 34 having a central axial bore for the piston rod 22. A sealing ring 35 is disposed between piston rod 22 and plug 34 and a sealing ring 36 is also arranged between said plug and the inner wall of the cylinder 24. A piston 37 is fixed to piston rod 22 and tits snugly within the interior of cylinder 24. One end of a coil spring 38 abuts the piston 37 and the other end of said spring is supported at the bottom of the cylinder. Two vertical grooves are formed in the inner wall of cylinder 24 and preferably disposed diametrically opposite each other. One of said grooves is designated in Fig. 4 by reference numeral 39. Adjacent the top of cylinder 24 a tube 40 communicates with the interior of the cylinder and a conduit is connected to tube 40 by means of a nut 41. A check valve is also arranged in tube 40 and may consist of a seat 42, a ball 43 and a pin 44.

The operation of the described mechanism will now be outlined starting with the elevated, open position of the breech block illustrated in Fig. 1. In this position, barrel 1 with its breech ring 2 is in its run-out position and breech block 6 is elevated to the position illustrated, thereby opening the barrel chamber, by means of an actuating arm, not shown, and simultaneously the spring within the spring casing 10 is placed under tension. An auxiliary stop device, not shown, operates to lock breech block 6 in its elevated position. After a projectile has been inserted into the barrel chamber, the breech block is released and by virtue of its weight and the tension of the spring within spring casing 10, it will be caused to move downwardly with considerable force and speed. Prior to engagement with the stop members 4 and 5, abutment faces 16a and 17a of breech block 6 strike the plungers 16 and 17 which are maintained in their normal upwardly protruding position of Fig. 1 by means of the springs 14 and 15. The lower ends of plungers 16 and 17 rest against the outer ends of levers 18 and 19 which are maintained normally in the elevated position of Fig. l by means of the piston rods 21 and 22 and the springs 38 within the cylinders 23 and 24. Corresponding to the elevated position of levers 18 and 19 the pistons 37 immediately underlie the closure plugs 34. It will be noted that the space between each of the pistons 37 and the bottom of a respective cylinder 23 and 24 as well as the space between each piston and a respective plug 34 are filled with oil.

As the abutment faces 16a and 17a of breech block `6 strike the plungers 16 and 17 during the downward movement of said breech block, said plungers are depressed, simultaneously depressing the levers 18 and 19, the piston rods 21 and 22 and the pistons 37. The downward movement of the pistons 37 is resisted by the oil conlined within each closed cylinder 23 and 24, the check valves 42-44 preventing escape of oil under pressure from within said cylinders. Consequently, the speed and impact of breech block 6 will be considerably reduced, since the upward movement of the oil contined beneath the pistons 37 is restricted to the vertical grooves 39. Thus by reason of the described arrangement and the reduction of the speed of the breech block 6 during the final part of its movement to closed position, the impact of the breech block against stop members 4 and 5 is kept to a minimum, thereby eliminating undesirable rebounding and oscillation of the breech block. Moreover, by reducing the stresses imposed on the stop members 4 and 5 to a minimum, the stop members need not be of massive and cumbersome construction.

Fig. 2 illustrates the position of the breech block 6 when it has completed its downward movement to close the barrel chamber, in which position a tiring pin (not shown) carried in recess 7 may tire a rammed projectile.

As the barrel 1 with its breech ring 2 recoils following the tiring of the gun, the breech block 6 normally moves to the elevated position of Fig. l, to be locked there pending loading and repetition of the cycle of operations described above. However, it might occasionally happen, because of some malfunctioning of the actuating mechanism, that the breech block 6 is not locked in the elevated position but would move downwardly again, thereby depressing the plungers 16 and 17. During the recoil and the return of the gun barrel to its run-out position of Fig. 1, the plungers 16 and 17 would therefore remain depressed. As the gun barrel approaches the run; out position, as illustrated in Fig. 3, the depressed plungers 16 and 17 will ride up on the backs of levers 18 and 19 to be ultimately disposed substantially in alignment with the piston rods 21 and 22 at the run-out position. Thus the plungers 16 and 17 are brought into operative alignment with the piston rods 21 and 22 without any possibility of damage to the parts by jamming or collision.

It will be noted that the check valves 42-44 within the cylinders 23 and 24 not only prevent the escape of oil from the cylinders when pistons 37 are moved downwardly during the downward stroke of breech block 6 but that they also serve to prevent backow of oil to the tank 30 upon return of said pistons to their normally elevated position, when the oil above the pistons will pass through the grooves 39 to the space beneath the pistons. Tank 30 serves to supply the cylinders 23 and 24 with oil under its own pressure.

The springs 14 and 15 secured to plungers 16 and 17 and the springs 38 associated with pistons 37 function merely as return springs to restore the respective members to their normally elevated positions. While it would be possible to employ springs as impact-absorbing members instead of oil in a closed hydraulic system as described hereinabove, such springs would of neccessity be large and heavy because of the high speed and impact of the breech block 6. Therefore, the substitution of impactabsorbing and speed-reducing spring members in the described arrangement is rarely practical.

Since certain modifications may be made in the breech block mechanism of the present invention without departing from the scope thereof, it is intended that all matter contained in the foregoing specification and shown in the accompanying drawings be interpreted merely as illustrative and not in a limiting sense.

What is claimed is:

l. In combination with a gun barrel having a breech ring dening a vertically extending breech opening therethrough, a breech block movable from an elevated open position to a lowered closed position within said breech opening, stop members disposedadjacent the lower end of said breech opening and engageable by said breech block for arresting said breech block-in the closed position thereof, a cushioning means engageable by the breech block for the last part of the downward movement thereof and yieldable in the directionof the said movement for reducing the speed and impact of said breech block prior to an engagement with said stop members, the said cushioning means comprising at least one plunger element movable in the same direction as said breech block, the said breech block having at least one abutment face adapted to engage the upper end of said plunger element prior to an engagement of said breech block withsaid stop members, an impact-absorbing member disposed ou a fixed part of the gun and beneath said plunger element, and a lever having one end pivoted to a fixed part of the gun and its other end interposed between the lower end of said plunger element and the upper end of said impactabsorbing member.

2. A device in accordance with claim 1, wherein the said impact-absorbing member comprises a closed chamber, a piston within said chamber, and a piston rod protruding from said chamber for operative' engagement with said other end of said lever.

3. A device in accordance with claim 1, wherein the said impact-absorbing member comprises a closed chamber, a piston within said chamber, and ya piston rod protruding from said chamber for operative engagement with said other end of said lever, the said chamber being filled with a fluid medium resisting a downward movement of said piston.

4. A device in accordance with claim l, wherein the said impact-absorbing member comprises a yclosed chamber, a piston within said chamber, and a piston rod protruding from said chamber for operative engagement with said other end of said lever, the said chamber being iilled with a iluid medium resisting a downward movement of said piston and having at least one passageway restricting the path of flow of said uid medium from beneath to above said piston upon a depression thereof.

5. A device in accordance with claim 1, wherein the said impact-absorbing member comprises a chamber and a piston arranged within said chamber and protruding therefrom for operative engagement with the outer end of said lever, the said chamber being filled with a uid medium resisting downward movement of said piston and having at least one passageway restricting the path of ow of said uid medium from beneath to above said piston upon depression thereof, said chamber being connected to a closed hydraulic system.

6. A device according to claim 1 for a recoiling gun barrel and wherein said plunger element participates in the recoil movement of the gun barrel, said lever forming a guide surface for the lower end of the plunger element to guide the latter out of and into a position above and in alignment with said impact absorbing member.

7. In combination with a gun barrel having a breech ring defining a breech opening extending transversely of the barrel, a breech block movable from an open position to a closed position within said breech opening, stop members disposed adjacent the closure end of said breech opening and engageable with the breech block for arresting said breech block in the closed position thereof, a cushioning means engageable by the breech block for the last part of the closing movement thereof and yieldable in the said direction for reducing the speed and the impact of said breech block prior to an engagement with said stop members, said cushioning means comprising at least one plunger element disposed in the path of the closing movement of the breech block and movable in the closing direction of said breech block, the breech block having at least one abutment face ladapted to engage the upper end of the plunger element immediately prior to engagement of said breech block with said stop members, and an impact absorbing means disposed in the downward path of said plunger element for actuation by the respective end thereof,isaid impact absorbing means comprising adamping cylinder and a spring loaded piston slideable therein and having a piston rod protruding from the cylinder, .said plungerY elementl engaging said piston rod for damping the movement ofthe plunger element.

8. In combination with a gun barrel having a breech ring defining a breech opening extending transversely of the barrel, a breech block movable from an open position to a closed position within said breech opening, stop members disposed adjacent the closure end of said breech opening and engageable with the breech block for arresting said breech block in the closed position thereof, a cushioning means engageable by the breech block for the last part of the closing movement thereof and yieldable in the said direction for reducing the speed and the impact of said breech block prior to an engagement with said stop members, said cushioning means comprising at least one plunger element disposed in the path of the closing movement of the breech block and movable in the closing direction of said breech block, the breech block having at least one abutment face adapted to engage the upper end of the plunger element immediately prior to an engagement of said breech block with said stop members, and an impact absorbing means disposed in the downward path of said plunger element for actuation by the respective end thereof, said impact adsorbing means comprising a closed chamber and a piston arranged within said chamber and protruding therefrom for operative contact with the end of said plunger element ropposite the breech block, said chamber being filled with a fluid medium resisting a movement of said piston in the direction of the cushioning movement of the plunger element and having in its wall at least one passageway restricting the path of flow of said fluid medium from beneath to above said piston upon a displacement thereof in the aforesaid direction.

9. In combination with a gun barrel having a breech ring defining a breech opening extending transversely of the barrel, a breech block movable from an open position to a closed position within said breech opening, stop members disposed adjacent the closure end of said breech opening and engageable with the breech block for arresting said breech block in the closed position thereof, a cushioning means engageable by the breech block for the last part of the closing movement thereof and yieldable in the said direction for reducing the speed and the impact of said breech block prior to an engagement with said stop members, said cushioning means comprising at least one plunger element disposed in the path of the closing movement of the breech block and movable in the closing direction of said breech block, the breech block having at least one abutment face adapted to engage the upper end of the plunger element immediately prior to engagement of said breech block with said stop members, and an impact absorbing means disposed in the downward path of said plunger element for actuation by the respective end thereof, said impact absorbing means comprising a chamber and a piston arranged within said chamber and protruding therefrom for operative engagement with the lower end of said plunger element opposite the breech block, said chamber being filled with a uid medium resisting a movement of said piston in the direction of the cushioning movement of said plunger element and having in its wall at least one passageway restricting the path of flow of said fluid medium from beneath to above said piston upon a displacement thereof, said chamber being connected to a closed hydraulic system.

10. A device according to claim 9, wherein a check valve is interposed between said chamber and said hydraulic system to prevent back iiow of tluid medium to said hydraulic system upon movement of said system.

(References on following page) References Cited in the le of this patent UNITED STATES PATENTS Vickers Oct, 29, 1946 Lippert June 9, 1953 FOREIGN PATENTS Great Britain Feb. 17, 1939 Great Bn'tain May 1, 1946 

